Method of making cork composition cartridge plugs



Feb. 5, 1946. H. PASCHKE ET AL 2,394,524

METHOD OF MAKING CORK COMPOSITION CARTRIDGE PLUGS Filed April 30, 1943 Patented Feb. 5, 1946 STTES PATENT OFFICE METHOD OF MAKING CORK COMPOSITION CARTRIDGE PLUGS Herbert Paschke and John W. Wiley, Lancaster,

Pa, assignors to Armstrong Cork Company, Lancaster, Pin, a corporation of Pennsylvania Application April 30, 1943, Serial No. 485,214

Claims.

Figure 4 is a plan view of a mold for shaping the plastic cork composition to the desired contour; and

Figure 5. is a view in elevation of the mold i1- lustrated in Figure 4.

Referring to the drawing, there is illustrated frangible core and a relatively hard, thin protec- 5 tive coating or shell covering the core. a cork composition cartridge plug designated Heretofore, cork composition cartridge plugs generally at 2. The cartridgeplug is composed have been composed of a core formed of coarsely of a core 3 formed of any relatively soft mateground baked cork particles of relatively low rial, such as coarsely ground cork of relatively tensile strength held together by a binder. A low tensile strength or any similar material, hard outer ring composed of finely ground cork adapted to be quickly broken up or otherwise deof relatively high tensile strength held together stroyed upon explosion of the charge, held tobye. binder has been placed about the readily gether by a binder. Preferably, the core 3 is frangible core and cemented thereto. In pracformed from corkboard-cork particles held totice, the core was formed from a mat of rela- 1'5 gether in the form of an integral mass by resin tively low tensile strength and the hard outer exuded during the baking operation or by an shell was out from a mat of relatively high tenadded binder. The core 3 is covered by a coat- .sile strength and cemented to the core. This ing or layer 4, preferably, a composition of high method of forming cork composition cartridge tensile strength composed of finely ground cork, plugs is very expensive for the procedure deheld together by a suitable binder. scribed results in a large loss of material. In In forming the cork cartridge plug of our inaddition, an excessive number of operations are vention, preferably, a sheet, strip or ribbon 5 of required to form the core and the shell, and to plastic cork composition is formed by any suit- .adhere the shell to the core and generally skilled able extruding device 6. The strip 5 is wrapped labor is required to perform such operations. about core 3 and the wrapped core is placed in The chief object or this invention is to provide a mold designated generally at l. Mold '5 inan improved method of forming cartridge plugs. cludes a base 8, and walls -9 connected by a suit- An object of this invention is to provide a method able hinge I0 so as to be movable inwardly and of forming cork composition cartridge plugs outwardly about the core. If desired, a top plate which is economical and readily performed by (not shown) may be provided to close the mold. unskilled labor. A further object is to provide The wrapped core is placed in the mold 7 and a method of making cork composition cartridge the walls 9 are closed thereabout by any suitplugs in which excessive loss or waste is obviated. able means such as handles II to shape the A still further object is to provide a method of wrapped strip 5 to desired contour. The article making cork composition cartridge plugs which is then removed from the mold and disposed on greatly reduces the cost of the finished product. a rack to dry if a volatile solvent type binder for This invention relates to a method of making the cork composition has been used; if a heat cork composition cartridge plugs in which the settable binder has been used in forming the steps comprise disposing plastic cork composiplastic cork composition, the shaped articles may tion about a shaped core, shaping the plastic be disposed in ovens and subjected to heat to set composition to the desired contour, and hardenthe binder. It will be understood our invention ing the composition to form a thin, relatively is not limited to the type of mold illustrated since hard coating about said core. any suitable means may be used to shape the The attached drawing illustrates a method of strip 5 to desired contour about the core 3. carrying out the present invention, in which It is essential in our invention that the com- Figure l is a view in elevation of a cork composition used as an outer coating be plastic and position cartridge plug prepared by the method moldable so as to be easily disposed about the of our invention; core, and be capable of setting to form a rela- Figure 2 is a view in elevation partially broken tively hard coating so as to withstand impact and away illustrating the shaped core wrapped with abrasive action. Such plastic composition may a plastic, moldable sheet of cork composition; be formed of any suitable material having the Figure 3 is a diagrammatic view of extruding characteristics required for the purpose; prefapparatus for extruding a strip or sheet of plaserably, it is formed of cork particles held together tic cork composition; by a binder composed of ethyl cellulose, a suitable plasticizer and a. volatile solvent. A satisfactory binder composition may be formulated as follows:

Parts by weight Ethyl cellulose 100 Plasticizer 20 to 40 Solvent 100 to 200 In place of ethyl cellulose, cellulose nitrate, cellulose acetate or other suitable plastic binders may be used. If desired, extenders for the binder such as rosin or Vinsol (oxidized rosin acids) may be used. The solvent is a mixture of'alcohol and toluol, although any suitable volatile solvents may be used. The plasticizer may be methyl abietate, although other plasticizers, such as tributyl phthalate, tributyl phosphate, or castor oil may be used as is well known in the industry.

As pointed out above, such plastic composition.

may be formed by mixing the cork particles and binder together in a suitable mixer, then extruding the plastic composition to form a plastic moldable strip, sheet, or ribbon 5. The strip 5 is disposed about the core 3, the wrapped core disposed in mold I and the plastic composition shaped to desired contour. With the binder disclosed above, the shaped article may be disposed on a rack to dry and set the binder by evaporation of the solvent. Evaporation of the solvent forms a thin, relatively hard coating about the core. To expedite drying, the shaped article may be placed in a heated oven.

It will be understood, of course, the cold plastic mass of cork composition may be spread, shaped or applied by any desirable means about the cork composition core. We have found that most satisfactory results are obtained by shaping the cold plastic mass into a thin strip and wrapping the strip about the core. Such procedure is expeditious and obviates waste since the strip may be severed into a desired length for wrapping about the core. If desired, the core may be disposed in a mold and the cold plastic mass packed thereabout, then shaped to desired contour by the applicationof pressure. r 7

While we have described our invention with particular reference to the use of a cold plastic mass having a binder dissolved in a volatile solvent, it will be understood binders adapted to be set by the application of heat may be used with satisfactory results. The only requirement is that the cork composition mass be plastic and adapted to be shaped to desired contour about the core. It will be understood the binder of the plastic composition is sufiicient to adhere the strip to the core and an additional adhesive or binder is not required.

- After the cork cartridge plug has been formed as described above, the hard coating may be ground or bufied to remove irregularities and to finish it to desired dimensions.

The chief advantage of our invention resides in the elimination of the waste heretofore deemed necessary in the manufacture of cork composition cartridge plugs. Our invention not only eliminates waste in the manufacture of cork composition cartridge plugs, but eliminates various machining operations heretofore deemed essential and thus aids in lowering the cost of the finished product.

While we have described and illustrated a preferred embodiment of our invention, it will be understood our invention is not limited thereto since it may be otherwise embodied or practiced within the scope of the following claims.

We claim:

1. In the method of making composition cork cartridge plugs having an inner shaped corkboard core and a thin; relatively hard cork com position outer layer thereon, the steps which comprise wrapping a strip of plastic cork composition formed of. cork granules and a binder about a shaped corkboard core, pressing the plastic cork composition to desired contour without substantial compression of said core, and hardening thecork composition binder to form a thin, relatively hard coating about said corkboard core.

2. In the method of making composition cork cartridge plugs, the steps which comprise wrapping a strip of plastic cork composition about a shaped corkboard core, placing the wrapped core in a mold, pressing the plastic composition to desired contour without substantial compression of said core, and hardening the composition to form a thin, relatively hard coating about said core.

3. In the method of making composition cork cartridge plugs, the steps which comprise forming cork particles, a binder, and a solvent for the binder into a strip of plastic cork composition, wrapping said strip about a shaped corkboard core, the binder of said plastic composition adhering the strip to said core, placing the wrapped core in a mold, pressing the plastic composition to desired contour without substantial compres-= sion of said core, and evaporating the solvent to form a thin, relatively hard coating about said core.

4. A method according to claim 3 in which the binder is composed of ethyl cellulose and a plasticizer therefor dissolved in a volatile solvent.

5. In the method of making cork composition cartridge plugs, the steps which comprise forming cork particles and a heat-settable binder into a strip of plastic cork composition, wrapping said strip about a shaped core, placing the wrapped core in a mold, pressing the plastic composition to desired contour, and heating the shaped article to form a thin, relatively hard coating about said core. 7

' HERBERT PASCHKE.

JOHN W. WILEY. 

